#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define rep(i, a, b) for (int i = (a); i <= (b); i++)
#define per(i, a, b) for (int i = (a); i >= (b); i--)
#define endl '\n'
const int N = 1e5 + 5;

int n, m;
int a[N];
ll b[N];
ll mn[N];
bool check(int avg) {
  rep(i, 1, n) b[i] = a[i] * 1000 - avg;
  rep(i, 1, n) b[i] += b[i - 1];
  rep(i, 1, n) mn[i] = min(mn[i - 1], b[i]);
  rep(i, m, n) if (b[i] >= mn[i - m]) return true;
  return false;
}
int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n >> m;
  rep(i, 1, n) cin >> a[i];
  int l = 1000, r = *max_element(a + 1, a + n + 1) * 1000;
  while (l <= r) {
    int mid = (l + r) >> 1;
    if (check(mid))
      l = mid + 1;
    else
      r = mid - 1;
  }
  cout << r;
  return 0;
}